Quantum Emitters in Two-Dimensional Materials

Quantum emitters in two-dimensional materials represent a rapidly evolving frontier in nanoscale photonics and quantum information science. Atomically thin semiconductors, most notably transition metal dichalcogenides (TMDCs), host tightly bound excitons whose confinement can be localised by defects, strain gradients or heterostructure moiré potentials. These discrete quantum systems can produce single photons or entangled pairs with high purity and brightness, offering on-chip integration prospects for quantum communication, sensing and computing. Recent advances have elucidated the microscopic interactions governing emitter stability, coherence and emission wavelength, paving the way for deterministic placement, electrical pumping and operation at elevated temperatures. The synergy of spin–orbit coupling, enhanced Coulomb interactions and light-matter integration in two dimensions underpins the unique capabilities of these platforms, from spin–photon interfaces to strongly coupled plasmonic and dielectric nanoantennas.

Research from Nature Portfolio

Recent studies have achieved real-time, atomic-scale insight into defect-bound states by combining lightwave scanning tunnelling microscopy with ultrafast spectroscopy, directly revealing how individual vacancy levels couple to lattice vibrations in a strained monolayer. Such measurements disentangle electron–phonon interactions at sub-picosecond timescales and lay the groundwork for coherent control of single-atom quantum bits. Complementary work using nanoscale indentation in monolayer WSe₂ has precisely located strain-induced single-photon sites, showing that dark exciton states can be spectrally shifted and hybridised with defect levels to yield near-unity emission purity. Further developments in site-controlled emitter arrays have demonstrated simultaneous defect and strain engineering to produce high-yield single-photon sources operating up to 150 K, with evidence of biexciton cascades and prospects for plasmonic or microcavity integration.

Quantum Emitters in Two-Dimensional Materials publication trend

The graph below shows the total number of articles in quantum emitters in two-dimensional materials across all publications each year (not limited to Nature Index journals).

Technical terms

Quantum emitter: A nanoscale system that emits photons one by one through discrete electronic transitions.

Exciton: A bound state of an electron and a hole in a semiconductor, behaving as a single optically active quasiparticle.

Transition metal dichalcogenide: A class of layered materials with the formula MX₂ (M = transition metal, X = chalcogen) exhibiting strong in-plane covalent bonding and direct bandgaps at the monolayer limit.

Strain engineering: The deliberate deformation of a crystalline lattice to modulate electronic band structure and localise optical transitions.

Moiré heterostructure: A superlattice formed by stacking two crystals with a small twist angle or lattice mismatch, producing periodic potential variations.

Photoluminescence: The process by which a material absorbs photons and re-emits them, often used to characterise excitonic transitions.

Purcell factor: A dimensionless measure of the enhancement of spontaneous emission rate of an emitter due to its electromagnetic environment.

References

1. Ultrafast atomic-scale scanning tunnelling spectroscopy of a single vacancy in a monolayer crystal. Nature Photonics (2024).
2. Photoluminescence imaging of single photon emitters within nanoscale strain profiles in monolayer WSe2. Nature Communications (2023).
3. Defect and strain engineering of monolayer WSe2 enables site-controlled single-photon emission up to 150 K. Nature Communications (2021).
4. High Q Hybrid Mie–Plasmonic Resonances in van der Waals Nanoantennas on Gold Substrate. ACS Nano (2024).
5. Strain-Induced Spatial and Spectral Isolation of Quantum Emitters in Mono- and Bilayer WSe2. Nano Letters (2015).
6. Discrete quantum dot like emitters in monolayer MoSe2: Spatial mapping, magneto-optics, and charge tuning. Applied Physics Letters (2016).